Method of processing color photographs by a silver dye-bleaching method

ABSTRACT

Leucobases of dyes can be used as dyes for photographic lightsensitive color film in a silver dye-bleaching system, without accompanying formation of fog, by processing the film, after dye bleaching, in a cleaning bath containing a water-soluble Nvinylpyrrolidone polymer, a peregal, or a lissolamine.

United States Patent Kanagawa, Japan [32] Priority Oct. 25, 1966 [3 3] Japan [54] METHOD OF PROCESSING COLOR PHOTOGRAPHS BY A SILVER DYE-BLEACHING METHOD 3 Claims, No Drawings s21 U.S.Cl 96/53 51 Int.Cl G03c7/00 [50] Field of Search [56] References Cited UNITED STATES PATENTS 2,263,012 11/1941 Schinzel 2,326,055 8/1943 Morris..... 2,376,297 5/1945 Weber 2,709,136 5/1955 Ganguin Primary ExaminerNorman G. Torchin Assistant Examiner-Mary F. Kelley Attorney-Sughrue, Rothwell, Mion, Zinn & Macpeak ABSTRACT: Leucobases of dyes can be used as dyes for photographic light-sensitive color film in a silver dyebleaching system, without accompanying formation of fog, by processing the film, after dye bleaching, in a cleaning bath containing a water-soluble N-vinylpyrrolidone polymer, a

peregal, or a lissolamine.

METHOD OF PROCESSING COLOR PHOTOGRAPHS BY A SILVER DYE-BLEACHING METHOD BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of processing color photographic materials by a silver dye-bleaching method and more particularly to a method of processing color photographs in which acleaning treatment is applied after silver dye bleaching.

2. Description of the Prior Art The formation of color photographic images by a silver dyebleaching method is based upon the fact that some kinds of dyes are destroyed by the presence of metallic silver. That is, silver'dye bleaching is generally carried out in the following manner. After light-exposing and developing a photographic gelatino silver halide emulsion layer, which has been uniformly colored by a suitable dye, such as, a light-sensitive color element having multiple silver halide layers each containing a yellow dye, a magenta dye, and a cyan dye respectively, the silver image thus formed is oxidized and simultaneously processed in a liquid containing an acid and a compound capable of forming a complex compound with silver ions, such as, thiourea, semicarbazide, thiosemicarbazide, potassium thiocyanate and the like. This has the action of reducing (bleaching) dyes at the silver image bearing portions or in a bleaching bath comprising an alkaline solution containing sodium sulfide, hydrosulfite, stannous chloride, thiourea and the like, and thereafter, the silver salt and remaining liquid are removed to provide a reversal dye image of the original silver image.

Therefore, by the aforesaid process, a unicolor image or a multiple color image can be formed. As a dye used in such a silver dye bleaching method, there is desired a dye which, (I) can be easily bleached by a bleaching bath in proportion to the photographic silver image, (2) becomes colorless by being completely bleached at a maximum silver image density, and (3) has high light fastness. For example, there are employed azo dyes, anthraquinone dyes, indigo dyes, phthalocyanine dyes, and the like. However, while the silver dye-bleaching method using such dyes has the merit that the color image obtained is faster to light, chemicals (acid and alkali) and moisture and also has better saturation and sharpness than those obtained by the so-called color developing method, it has the fault that, since the dye has a color from the first, the dye absorbs light to be absorbed by the silver halide to some extent, and hence, a light-sensitive element having a high sensitivity cannot be obtained.

Such a fault, however, can be removed by using a colorless compound formed by the reduction of the dye, i.e., a leucobase of dye. That is, the dye is first incorporated in an emulsion as its leucobase, and then after exposure, it is colored by oxidation in an appropriate step. Thereafter, the dye thus colored is converted into the leucobase again at the silver image portion by the dye bleaching processing, and the leucobase is removed from the light-sensitive emulsion layer to provide a colored image.

In other words, the dye employed in the method is one capable of forming a stable leuco derivative by reduction, and also providing the original dye simply by the oxidation of the leuco derivative. As typical examples of the dye, there are illustrated diphenylmethane dyes, triphenylmethane dyes, indigo dyes and other vat colors.

However, employing the aforesaid dyes capable of easily forming the leuco derivative, is accompanied by the following faults, as compared with the case of using dyes which do not form a stable leucobase, but are decomposed under usual conditions. That is, different from the case of azo dyes, dyes capable of forming stable leucobases are not decomposed by the dye-bleaching processing and stay as leucobases in the lightsensitive emulsion layer. If the leucobase is not completely removed from the light-sensitive emulsion layer, the leucobase is converted into the colored dye again by the subsequent silver dye-bleaching procedure or air oxidation, which causes fogs. Even though the light-sensitive emulsion layer containing such a leucobase is washed with water for a long period of time after dye bleaching, there remain fogs of an optical transmission density of higher than 0.2.

Therefore, an object of this invention is to provide a process of completely removing the leucobase of a dye in a light-sensitive emulsion layer in color photographic processings after subjecting the photographic light-sensitive color element containing the stable leucobase of dye to a silver dye bleaching process.

SUMMARY OF THE INVENTION Thus, according to the present invention, after processing by silver dye bleaching, a photographic light-sensitive color element, having on a support a monolayered or multiple layered silver halide emulsion layer containing the leucobases of dyes, the color element thus processed is further processed in a cleaning bath containing a polymer of water-soluble N- vinylpyrrolidone, a copolymer of water-soluble N-vinylpyrrolidone and another monomer, a peregal or a lissolamine, whereby the dye-bleached products remaining in the emulsion layer or emulsion layers, after the dye-bleaching procedure, are completely removed therefrom.

DETAILED DESCRIPTION OF THE INVENTION As the copolymer of water-soluble N-vinylpyrrolidone and other monomer incorporated in the aforesaid cleaning bath, there are illustrated copolymers of water-soluble N-vinylpyrrolidone and a vinyl ester, such as, vinyl acetate, vinyl propionate, or vinylbutyrate; an acrylic acid ester, such as a methyl ester, ethyl ester, butyl ester, or Z-ethyI-hexyl ester; a methacrylic acid ester, such as, methyl ester, ethyl ester, butyl ester, or 2-ethyl-hexyl ester; an acrylamide derivative, such as N-methylacrylar'nide, N-ethylacrylamide, N-N-diethylacrylamide, N-butylacrylamide, or acryloylmorpholine; and a methacrylamide derivative, such as, N-methylmethacrylamide, N-ethylmethacrylamide or methacryloylmorpholine. In this case, it'is very preferable to employ the copolymer having a monomer ratio to N-vinylpyrrolidone of 10-30 mol percent, but the invention shall not be limited to the preferred copolymer. Cop'olymers having any monomer ratios may be mula:

RO(CH CH O),,H or

RQ-O (CHgCH10)nH wherein R is an alkyl group and n is an integer indicating the polymerization degree of 'the ethyleneoxy group.

As the examples of the peregals, there are illustrated Peregal O, Peregal OK, Peregal ON, Peregal KBhe and Peregal C (trade names of LG. C0,).

Further, as the lissolamines used in this invention there are illustrated octadecylpyridinium bromide and tridecyltrimethylammonium bromide. However, it should be understood that the compounds incorporated in the cleaning bath of this invention are not limited to only the above-mentioned compounds, but there may be used any water-soluble compounds within the above-described classes capable of completely removing from silver halide emulsion layers the dye-bleached products remaining in the emulsion layers after the dye-bleaching processing.

The proportion of the water-soluble compound to be incorporated in the aforesaid cleaning bath of this invention may be varied widely according to the kind of compound, but is preferably from 5 to 50 g. and most preferably 10 to 30 g. per 1 liter of the cleaning bath. 7

Moreover, it is possible that instead of incorporating the aforesaid compound in the cleaning .bathof this invention,.the.

compound is previously incorporated in the emulsion layers, intermediate layers or a yellow filter layer of a photographic light-sensitive color element.

Further, the process of this invention is particularly effective for processing a photographic light-sensitive color element containing a stable leucobase of dye or stable leucobases of dyes and photographic light-sensitive color elements to be processed by a silver dye bleaching, but may be effectively applied to the processing of other photographic light-sensitive elements containing azo dyes which are not converted into the stable leucobases for completely removing a small quantity of dye-bleached products remaining undecomposed therein after dye bleaching.

As the dyes incorporated in the photographic light-sensitive color elements in a silver dye-bleaching method and capable of forming stable leucobases, there are illustrated, (1) sulfide dyes such as sulfide vat dye, (2) a vat dye, such as solubilized vat dye, (3) a triarylmethane or diphenylmethane dye, (4) an oxazine dye, an azine dye, thiazole dye, a quinoline dye, an acridinedye, an xanthene dye, and phthalocyanine dye. The following are practical examples of the effective dyes to be employed in the process of this invention, but the dyes to be used in this invention are not limited to them only.

Thus, as the sulfide dyes there are illustrated yellow dyes, such as, Sulfur Yellow-2 of color index (C.l. No. 53,120, Sulfur Yellow-4 of C.l. No. 53,160, Sulfur Yellow-8 of C.l. No. 53,226. and the like; magenta dyes such as Sulfur Red-2 of C.l. No. 53,260 Sulfur Violet-l of C.l. No. 53,410, Sulfur Violet-4 ofC.I. No. 53,700, Sulfur Violet 3 ofC.I. No. 53,780, and the like; and cyan dyes such as Sulfur Blue-l4 of C.l. No. 53,400, Sulfur Green- 6 of C.l. No. 53,530, Sulfur Blue-l of C.l. No. 53,540 and the like.

As the vat colors there are illustrated yellow dyes, such as, lndigosol Yellow HCGN ofC.I. No. 56,006, Indigosol Golden Yellow lGK of C.l. No. 59,101,1ndigosolYellow- 2GB of C.l. No. 61,726, Algosol Yellow GCA-CF of C.l. No. 67,301, lndigosol Yellow V of C.l. No. 60,531,1ndanthrene Yellow 461- of C.l. No. 68,420, ldanthrene Yellow G of C.l. No. 70,600, Mikethrene Yellow GC ofC.1. No. 67,300, lndanthrene Yellow of C.l. No. 68,405 and the like; magenta dyes such as lndigosol Brilliant Pink IR of C.l. No. 73,361, lndigosol Violet lRHR of C.l. No. 73,386, lndigosol Violet R of C1. No. 59,321, lndigosol Red Violet IRRL of C.l. No. 59,316, indigosol Red lFBB of C.l. No. 67,001, lndanthrene Red Violet of C.l. No. 67,895, Mikethrene Brilliant Violet BBK of C.l. No. 63,355, and the like; and cyan dyes such as lndanthrene Turquoise Blue 3G'K of Cl. No. 67,915, lndanthrene Blue 56 of C.l. No. 69,845,1ndanthrene Blue GCD of C.l. No. 69,810 and the like.

As the diphenylmethane dyes there are illustrated such yellow dyes, such as, Basic Yellow 2 of C.l. No. 41,000, Basic Yellow 3 of C.l. No. 41,005 and the like. As the triphenylmethane dyes there are illustrated magenta dyes, such as, Acid Blue 34 ofC.I. No. 42,561, Acid Violet 21 of C.l. No. 42,580 and the like and cyan dyes, such as, Basic Green 4 ofC.I. No. 42,000, Acid Green 11 of C.l. No. 49,039, Acid Green 13 of C.l. No. 42,046, Acid Green 3 ofC.I. No. 42,051 and the like.

Also, as the oxazine dyes, there may be used cyan dyes, such as, Basic Blue 4 of C.l. No. 51,004, Basic Blue 12 of C.l. No. 51,180 and the like or magenta dyes such as Mordant Violet 50 of C.l. No. 51,055, Mordant Violet 35 of C.l. No. 51,025 and the like.

As the azine dyes there are illustrated magenta dyes, such as, Basic Red 5 of C.l. No. 50,040, Basic Violet of C.l. No. 50,055, Basic Violet 5 C.l. No. 50,205, Basie Violet 8 of C.l. No. 50,210 and the like. As the thiazole dyes there are illustrated yellow dyes, such as, Basic Yellow 1 of C.l. No. 49,005 and the like. As quinoline dyes there are illustrated yellow dyes, such as, Solvent Yellow 33 of C.l. No. 47,000. As the acridine dyes there are yellow dyes, such as, Basic Orange 14 of C.l. No. 46,005, Basic Yellow 7 of C.l. No. 46,020 and the like.

Furthermore, as the zanthene dyes there may be used magenta dyes, such as, Basic Red 11 of C.l. No. 45,050, Basic Red 8 of C.l. No. 45,150. Basic Violet ll of C.l. No. 45,175 and the like, and also, as the phthalocyanine dyes there are illustrated Vat Blue 29 of C.l. No. 74,140, and the like.

Now, the practice of the invention will be explained with reference to the following examples:

EXAMPLE 1 Potassium Bichromate 5.0 g. Concentrated Sulfuric Acid 5.0 ml.

Water To Make 1,000 ml.

1n this way, the developed silver was removed from the lightsensitive emulsion layers and at the same time the leucobases of the dyes were uniformly oxidized and converted into the original dyes.

Thereafter, the element was processed for 4 minutes in a bath having the following composition:

Sodium Sulfite (anhydrous) Water To Make 50.0 g. 1,000 ml.

After washing with water for 4 minutes, the element was dye bleached for 7 minutes in a bath having the following composition:

Stannous Chloride 40.0 g. Sodium Hydroxide 50.0 g. Triethanolamine 100.0 ml. Anthraquinone 0.1 Water To Make 1,000 ml.

In this way, the dyes were reduced again to the leucobases at the portions bearing the remaining silver halides.

A secondary development may be conducted before the dye bleaching.

In this case, the reduction products remaining in the lightsensitive emulsion layers were completely removed therefrom by processing the element for 10 minutes in a cleaning bath having the following composition:

Poly-N-vinylpyrrolidone 30.0 g. Sodium Sulfate (anhydrous) 20.0 g. Sodium Sulfate 30.0 Water To Make 1,000 ml.

in the aforesaid cleaning bath of this example, sodium sulfite was added to prevent the leucobases from being reduced in the processing and from being air-oxidized to form insoluble precipitates. Also, sodium sulfate was used to increase the effect of the cleaning procedure by salting out the complex salts of polyvinyl pyrrolidone and the leucobases.

After washing with water for 10 minutes, the element was processed in a bath having the following composition, for 7 minutes:

Sodium Acetate (anhydrous) 20.0 g. Potassium Alum 30.0 g. Borax 10.0 g. Potassium Ferricyanide 30.0 g. Potassium Bromide 15.0 g. Water To Make 1,000 ml.

After washing with water for 4 minutes, the element was processed for 4 minutes in a conventional acid hardening fixing bath, washed with water sufficiently, and dried. The clear colored image thus obtained was a negative image.

EXAMPLE 2 Ferric Chloride 27.0 g. Concentrated Hydrochloric Acid 20.0 ml. Potassium Bromide l0.0 g. Water to Make L000 ml.

In this way, the developed silver was oxidized again to the silver halide, and, at the same time, the leucobases of dyes were colored by oxidation throughout the layers.

After washing with water, the element was subjected, as in example 1, to dye bleaching processing in the cleaning bath, and silver bleaching. The clear colored image thus obtained was a positive image.

EXAMPLE 3 The procedure as in example I was repeated, using as a cleaning bath a bath having the following composition Poly( NVinylpyrrolidone-Vinyl Acetate(8:2 Copolymcr) 10.0 g. Sodium Sull'tte (Anhydrous) 20.0 g. Sodium Sulfate 30.0 g. Water to Make L000 ml.

Results substantially similar to those of example 1 were obtained.

EXAMPLE 4 The same procedure as in example I was repeated, using as a cleaning bath a bath having the following composition:

Poly(N-Vinylpyrrolidone-Methyl Acrylatn) (3 :2 Copolyiner) l -s s- Sodium sulfite (anhydrous) 20.0 Sodium Sulfate 30.0 g. Water to Make L000 ml.

Results substantially similar to those of example l were obtained.

EXAMPLE 5 The procedure of example I was repeated, using as the compound to be incorporated in the cleaning bath the following compounds, that is, Poly(N-Vinylpyrrolidone-Butylmethacrylate) (9:l copolymer), Poly(N-Vinylpyrrolidone- Acrylamide) (8:2 copolymer), Poly(N-Vinylpyrrolidoneacryloylmorpholine) (7:3 copolymer), Poly(N-Vinylpyrrolidone-potassium Styrenesulfonate) (8:2 copolymer), the Peregals, Octadecylpyrridinium Bromide, and Tridecylmethylammonium Bromide.

In any case, the colored images obtained without using the foregoing cleaning baths had fog densities of higher than 0.2 in optical transmission density, whereas when the cleaning baths were used as in the examples, the fog density could be maintained at a level of less than 0.08.

What we claim is:

1. In a method of processing by a silver dye-bleaching technique, a photographic light-sensitive color element having on a support a single photographic silver halide emulsion layer containing a leucobase of a dye or multiple photographic silver halide emulsion layers containing leucobases of dyes,

the rocess which comlprises, after dye bleaching cleaning the ligh -sensit1ve color e ement III a cleaning bah capab e of removing the leucobase material from the light-sensitive element, said cleaning bath containing from 5 to 50 grams per liter of a material selected from the group consisting of a water-soluble polymer of N-vinylpyrrolidone and a water soluble copolymer of N-vinylpyrrolidone. 2. The process according to claim 1 wherein said copolymer of N-vinylpyrrolidone is selected from copolymers of N-vinylpyrrolidone and butylmethacrylate, copolymers of N-vinylpyrrolidone and acrylamide, copolymers of N-vinylpyrrolidone and acryloyomorpholine, and copolymers of N-vinylpyrrolidone and potassium styrenesulfonate.

3. The process according to claim 1 wherein said cleaning bath further contains sodium sulfite and sodium sulfate. 

2. The process according to claim 1 wherein said copolymer of N-vinylpyrrolidone is selected from copolymers of N-vinylpyrrolidone and butylmethacrylate, copolymers of N-vinylpyrrolidone and acrylamide, copolymers of N-vinylpyrrolidone and acryloyomorpholine, and copolymers of N-vinylpyrrolidone and potassium styrenesulfonate.
 3. The process according to claim 1 wherein said cleaning bath further contains sodium sulfite and sodium sulfate. 